Ever since the centuries old inventions of locks, there have been efforts to defeat locks. These methods have included skeleton keys and picking of locks. Skeleton keys were particularly notorious with the old type of keys such as those illustrated in the 1859 patent to Schroeder, U.S. Pat. No. 24,523, and in Schmid, U.S. Pat. No. 1,819,059. In fact, both such patents were directed to means of blocking the key hole to prevent the use of other keys, such as skeleton keys.
This concept was continued into the lock art upon the development of keys having plurality of teeth with random variation in their elevation from the rotation axis of the key. Examples include the 1869 patent by Shepardson, U.S. Pat. No. 87,714, Heiden, U.S. Pat. No. 1,713,602, and Reisner, U.S. Pat. No. 3,475,934. Other art known as to Applicant include Keil, U.S. Pat. No. 1,867,361, Mason, U.S. Pat. No. 2,561,029, and Eichenauer, U.S. Pat. No. 1,956,438. Much of the problem with conventional locks has been that they are susceptible to being picked, even if they are somehwat more resistant to skeleton keys. It is fairly well recognized that most conventional house and automotive locks can be picked by a skilled thief in a matter of minutes. In fact, the number of issued patents directed to locking key holes since the invention of modern locks suggests to Applicant a tacit admission that present lock designs are inadequate and subject to significant improvement without significant cost increase or consumer inconvenience. One area of particular concern is that the resiliently urged pins in most present locks are in alignment with the slot into which the key is inserted, thereby exposing same to manipulation by a thief. Some locks are manufactured with two sets of pins, the ends of all of which must meet at the junction of inner and outer cylinders in order for the lock to be opened, but such a lock is still subject to manipulation by a thief, particularly if inner and outer cylinders are not in very close fitting relationship, because the pins are still in alignment with the key slot. Moreover, this type of construction is expensive, particularly if inner and outer cylinders are machined to tight tolerances for close fitting relationship. This latter design is not known by Applicant to be patented, but is in widespread use in better locks.
There is no locking mechanism known to the Applicant wherein such pins are shielded from access by the mechanism of the lock. Indeed, the foregoing references and description represent the totality of the art in this field known to the Applicant.